The magnifying ruler is a great multipurpose tool for editing and formatting text and data. One outside edge is a 15" ruler marked with increments down to 1/32" , 1/16" and 1/8". The other is a 38cm ruler with millimeter hash marks. In between are a magnifying bar to highlight text, a character-counting scale to use horizontally across a page, and a line-counting scale to use vertically. The character-counting scale is marked in 1/10" increments. The line-counting scale is marked in 1/6" increments with 1/12" hash marks.The magnifying ruler is a great multipurpose tool for editing and formatting text and data. One outside edge is a 15" ruler marked with increments down to 1/32" , 1/16" and 1/8". The other is a 38cm ruler with millimeter hash marks. In between are a magnifying bar to highlight text, a character-counting scale to use horizontally across a page, and a line-counting scale to use vertically. The character-counting scale is marked in 1/10" increments. The line-counting scale is marked in 1/6" increments with 1/12" hash marks.